Linear compressor

ABSTRACT

A linear compressor having a stator comprising a coil body for generating a magnetic field when electric current is supplied to the stator, and outer cores disposed on the coil body while surrounding the coil body such that a magnetic flux passes therethrough. The coil body is formed in the shape of a hollow cylinder. The coil body is made of wound electric wires. The coil body is provided with a form-maintaining member for maintaining the shape of the coil body, by which the outer cores are supported. An impregnant, such as varnish, is used as the form-maintaining member. The impregnant is penetrated into gaps between electric wires, and is then solidified so that the shape of the coil body is firmly maintained.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.2004-18069, filed on Mar. 17, 2004 in the Korean Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a linear compressor, and, moreparticularly, to a linear compressor having a stator for moving a movingmember connected with a piston forward and backward.

2. Description of the Related Art

Generally, a compressor is used to compress a coolant and discharge thecompressed coolant to the outside in a refrigerating cycle wherecompression, condensation, expansion, and evaporation processes areconsecutively carried out with the coolant as a medium. A linearcompressor is used to compress a coolant by means of a linear motor thatis capable of carrying out a rectilinear movement, by which a piston islinearly reciprocated.

The conventional linear compressor serving to perform theabove-mentioned functions comprises: a compressing unit for compressinga coolant in a hermetically sealed container; and a driving unit fortransmitting power to the compressing unit.

The compressing unit comprises: a cylinder block having a compressionchamber defined therein; and a piston disposed in the compressionchamber of the cylinder block such that the piston is moved forward andbackward to compress the coolant. To one side of the cylinder block isattached a cylinder head having an inlet chamber and outlet chamberdefined therein.

The driving unit comprises: a stator for generating a magnetic fieldwhen electric current is supplied to the stator; an inner core disposedwhile being spaced a prescribed distance from the stator for generatinga magnetic flux together with the stator; and a moving member disposedbetween the stator and the inner core for driving the piston.

The stator of the conventional compressor will hereinafter be describedin more detail. The stator comprises: a cylindrical bobbin; and a coilwound on the outer circumference of the bobbin. On the bobbin aremounted outer cores in the circumferential direction of the bobbin.

The bobbin is provided at the top and bottom parts thereof with coremounting grooves, into which the outer cores are engaged so that theouter cores are fixedly attached to the bobbin.

In the conventional linear compressor with the above-statedconstruction, there is generated a magnetic field at the outer coreswhen electric current is supplied to the coil. The moving member islinearly moved by means of magnetic interaction between the magneticfield and the moving member. At the same time, the piston connected tothe moving member is reciprocated in the compression chamber so that thecoolant is compressed.

In the stator of the conventional compressor, however, the outer coresare mounted on the bobbin. As a result, the outer cores may deviate fromtheir originally mounted positions when the bobbin is deformed due toheat generated during operation of the compressor.

Consequently, gaps between the moving member and the outer cores may notbe constantly maintained, whereby the entire efficiency of the linearmotor is decreased.

Furthermore, the compressor may be damaged when the moving memberdirectly collides with the outer cores.

SUMMARY OF THE INVENTION

Therefore, it is an aspect of the invention to provide a linearcompressor that is capable of preventing deformation of a stator due toheat generated when the compressor is operated.

In accordance with an aspect, the present invention provides a linearcompressor comprising: a piston reciprocated in a cylinder forcompressing a coolant; a moving member reciprocated along with thepiston; and a stator electro-magnetically interacting with the movingmember for driving the moving member, wherein the stator comprises: acoil body formed of wound electric wires; a core disposed on the coilbody; and a form-maintaining member for maintaining the shape of thecoil body so that the core is supported by means of the coil body.

Preferably, the form-maintaining member is an impregnant penetratedbetween the electric wires forming the coil body.

Preferably, the coil body and the core are fixedly attached to eachother with an injection-molded member filled between the coil body andthe core by means of injection molding.

Preferably, the coil body is formed in the shape of a hollow cylinder,the core comprises a plurality of cores spaced apart from each otheralong the outer circumference of the coil body, and the injection-moldedmember is filled between the cores.

Preferably, each of the cores is provided at the side thereof oppositeto the moving member with a pair of teeth parts, the injection-moldedmember being filled in a separated space defined between the teethparts.

Preferably, the injection-molded member is formed of a resin material.

Preferably, the compressor further comprises a protection memberdisposed between the core body and the coil for protecting the coilbody.

Preferably, the protection member is made of paper.

BRIEF DESCRIPTION OF THE DRAWINGS

The above aspects, and other features and advantages of the presentinvention will become more apparent after reading the following detaileddescription when taken in conjunction with the drawings, in which:

FIG. 1 is a sectional view of a linear compressor according to thepresent invention;

FIG. 2 is a perspective view illustrating a coil body of the linearcompressor according to the present invention;

FIG. 3 is a sectional view illustrating the coil body of the linearcompressor according to the present invention;

FIG. 4 is an exploded perspective view illustrating how to combine coreswith the coil body of the linear compressor according to the presentinvention;

FIG. 5 is a perspective view illustrating combination of the cores andthe coil body of the linear compressor according to the presentinvention by means of an injection-molded member; and

FIG. 6 is a sectional view illustrating a protection member disposedbetween each core and the coil body of the linear compressor accordingto the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the present invention will now be described indetail with reference to the accompanying drawings.

FIG. 1 is a sectional view of a linear compressor according to thepresent invention.

Referring to FIG. 1, the linear compressor according to the presentinvention comprises: a compressing unit 20 for compressing a coolant ina hermetically sealed container 10; and a driving unit 30 for drivingthe compressing unit 20.

The compressing unit 20 comprises: a cylinder block 21 having acompression chamber 21 a defined therein; and a piston 22 disposed inthe compression chamber 21 a of the cylinder block 21 such that thepiston 22 is moved forward and backward. To the bottom part of thecylinder block 21 is attached a cylinder head 23 having an inlet chamber(not shown) and outlet chamber (not shown) defined therein.

The driving unit 30 comprises: an inner core 31 disposed at the outsideof the cylinder block 21; a stator 40 surrounding the inner core 31while being spaced a prescribed distance from the outer circumference ofthe inner core for generating a magnetic field; and a moving member 50having a magnet 51 disposed such that the moving member is verticallyreciprocated by means of a magnetic flux between the inner core 31 andthe stator 40. Preferably, the driving unit 30 is a linear motor.

The stator 40 according to the present invention comprises: a coil body41 for generating a magnetic field when electric current is supplied tothe stator 40; and outer cores 42 disposed on the coil body whilesurrounding the coil body 41 such that a magnetic flux passestherethrough.

Referring to FIG. 2, the coil body 41 is formed in the shape of a hollowcylinder. The coil body 41 is made of wound electric wires 41 a. Thecoil body 41 is provided with a form-maintaining member 41 b formaintaining the shape of the coil body 41, as shown in FIG. 3, by whichthe outer cores 42 are supported.

An impregnant, such as varnish, may be used as the form-maintainingmember 41 b. The impregnant is penetrated into gaps between electricwires 41 a, and is then solidified so that the shape of the coil body 41is firmly maintained. The varnish is a type of paint, which is made of anatural or synthetic resin dissolved in a solvent. The varnish forms atransparent lustrous film.

Along the outer circumference of the impregnated coil body 41 aredisposed a plurality of outer cores 42, spaced apart from each other asshown in FIG. 4. Each outer core 42 comprises an upper outer core part42 a and a lower outer core part 42 b. To the coil body are attached theouter core parts 42 a and 42 b in correspondence to each other. Theouter core parts 42 a and 42 b are provided at the sides thereofopposite to the moving member 50 with teeth parts 42 c and 42 d,respectively, by which the areas of the outer cores 42electro-magnetically interacting with the moving member 50 are increasedwith the result that the stroke of the piston 22 is effectivelyincreased.

As shown in FIG. 5, the coil body 41 and the outer cores 42 are fixedlyattached to each other with an injection-molded member 43, which isfilled between the coil body 41 and the outer cores 42 by means ofinjection molding. The injection-molded member 43 is made of a resinmaterial. The injection-molded member 43 is filled between the outercores 42 and in separated spaces defined between the teeth parts 42 cand 42 d of the outer cores 42 so that the outer cores are securelyattached to the coil body 41.

Referring to FIG. 6, the stator 40 according to the present inventionfurther comprises a protection member 44 disposed between the coil body41 and each outer core 42 for surrounding the coil body 41 so thatdamage to the coil body is prevented. Preferably, the protection member44 may be a thin paper, by which a magnetic flux smoothly flows betweenthe coil body 41 and the outer core 42.

Now, the operation and effect of the linear compressor with theabove-stated construction according to the present invention will bedescribed.

When electric current is supplied to the coil body 41 made of woundedelectric wires 41 a, there is generated a magnetic field. The magneticfield interacts with a magnetic filed generated by means of the magnet51 mounted in the moving member 50 so that the piston 22 is verticallyreciprocated. As the piston 22 is reciprocated, the coolant isintroduced, compressed, and discharged.

At this time, the coil body 41 and the outer cores 42 are securelyattached to each other with the injection-molded member 43 made of aresin material and formed by means of injection molding. Consequently,shake or separation of the outer cores 42 from the coil body 41 due tothe vibration generated during the operation of the compressor isprevented.

In the stator 40 according to the present invention, the outer cores 42are directly attached to the coil body without an additional bobbin.Consequently, deformation of the stator 40 due to heat generated duringthe operation of the compressor is prevented.

As apparent from the above description, the present invention provides alinear compressor wherein outer cores are directly attached to a coilbody without an additional bobbin, the outer cores being securely fixedto the coil body with an injection-molded member formed by means ofinjection molding.

Consequently, deformation of a stator due to heat generated during theoperation of the compressor is prevented, whereby gaps between a movingmember and the outer cores are constantly maintained. As a result,initial gaps between the moving member and the outer cores are set tothe minimum, whereby the efficiency of a linear motor is improved.

Furthermore, the linear compressor according to the present inventionrequires no bobbin, whereby the number of winding electric wires, whichform the coil body, is increased. Consequently, output of the linearmotor is increased, the manufacturing process is simplified, and themanufacturing cost is reduced.

Although the preferred embodiment of the invention has been disclosedfor illustrative purposes, those skilled in the art will appreciate thatvarious modifications, additions and substitutions are possible, withoutdeparting from the scope and spirit of the invention as disclosed in theaccompanying claims.

1. A linear compressor comprising: a piston reciprocated in a cylinderfor compressing a coolant; a moving member reciprocated along with thepiston; and a stator electro-magnetically interacting with the movingmember for driving the moving member, wherein the stator comprises: acoil body formed of wound electric wires; a core disposed on the coilbody; and a form-maintaining member for maintaining the shape of thecoil body so that the core is supported by means of the coil body. 2.The compressor according to claim 1, wherein the form-maintaining memberis an impregnant penetrated between the electric wires forming the coilbody.
 3. The compressor according to claim 1, wherein the coil body andthe core are fixedly attached to each other with an injection-moldedmember filled between the coil body and the core by means of injectionmolding.
 4. The compressor according to claim 3, wherein the coil bodyis formed in the shape of a hollow cylinder, the core comprises aplurality of cores spaced apart from each other along the outercircumference of the coil body, and the injection-molded member isfilled between the cores.
 5. The compressor according to claim 4,wherein each of the cores is provided at the side thereof opposite tothe moving member with a pair of teeth parts, the injection-moldedmember being filled in a separated space defined between the teethparts.
 6. The compressor according to claim 3, wherein theinjection-molded member is formed of a resin material.
 7. The compressoraccording to claim 1, further comprising a protection member disposedbetween the core body and the coil for protecting the coil body.
 8. Thecompressor according to claim 7, wherein the protection member is madeof paper.